The present invention relates to an automated document feeder (ADF) for use with an image forming apparatus such as copy machine to feed documents onto a transparent glass or platen of the copy machine and then discharging the same therefrom.
Japanese Patent Laid-Open Publication (Tokkaihei) No. 4-235836 discloses an automated document feeder which includes a document support for supporting a stack of documents, a feed roller disposed above the document tray and a lifting plate for lifting the documents on the document support to bring the topmost document into contact with the feed roller, thereby upon rotation of the feed roller the topmost document is fed out from the document support.
To facilitate the users to set, re-set and add documents on the document support and to remove the same therefrom, the conventional automated document feeder is so designed that the lifting plate normally occupies a lowered position to keep the documents out of contact with the feed roller and, once an instruction is made from a start switch to feed the document, the lifting plate moves up to bring the topmost document into contact with the feed roller. However, the conventional lifting movement of the documents takes a longer time, which delays the beginning of the document feeding.